Computer systems are increasingly requiring computer users to input very large numbers in the course of using the computer system. For example, a user who is purchasing a product via the Internet may be required to enter a credit card number, which can be 16 digits in length. In general, with the increasing use of the Internet and similar networks, the need for users to input very large numbers is increasing. For example, electronic mail addresses on the Internet and encryption keys used to secure messages sent via the Internet may be represented as very large numbers. Also, computer programs may display very large numbers to help identify an error that has occurred. The user would then report the displayed number to a programmer so that the error can be corrected.
It can be, however, very difficult for users to remember very large numbers. For example, an electronic mail address of "3481.269.321" cannot be easily remembered. Moreover, it is even more difficult to remember several very large numbers. Consequently, users often write down these very large numbers rather than remembering them. The writing down of such numbers can have several disadvantages. First, the user may not have easy access to pencil and paper. Second, even if the number is written down on paper, the user may lose the paper or may not have it immediately available when it is needed. Third, the writing down of the number can compromise security. For example, the writing down of an encryption key can compromise the security of the system because an unauthorized user can then get access to the written key.
Several techniques have been developed to help users remember various large numbers so that the writing down of the numbers can be avoided. For example, certain telephone numbers have a portion represented as a word so that the telephone number can be more easily remembered. For example, the telephone number 1-800-265-5328 can be more easily remembered as 1-800-COLLECT. While such a representation provides a useful mechanism to aid a user in remembering the telephone number, very few telephone numbers can be represented by words, and even fewer by meaningful words. To generate such a telephone number, one would identify the word and then convert the word to the corresponding telephone number. A similar approach is used for assigning personal identification numbers for accessing automated teller machines. A typical personal identification number is four digits long. Rather than assigning any four-digit number as a personal identification number, a four-letter word is first selected and then converted to the corresponding digits of a numeric keypad. For example, word "SLUG" may be selected to represent the personal identification number of 7584. A person can, in general, more easily remember the word "SLUG," rather than the number 7584. Because words are easier to remember than numbers and non-word character sequences, some computer systems generate user passwords that are a sequence of words. For example, a computer system may generate a password for a user comprising the words "SLUG TUNE," which is easier to remember than the password "75848863."
Although these various schemes have been useful in helping a user remember, they each have limited applicability (e.g., meaningful, 7-letter words for telephone numbers). It would be desirable to have a general mechanism in which very large numbers could be more easily remembered by a user.